Carburetor



1963 F. P. SCHLICHTING 3,077,341

CARBURETOR Filed April 1, 1960 IIIII I'l e! FIG.2. 49

44 46 47 57 34 V w E5555 U.3/ AZZ }?}77 3 {33 L36 (45 4 3l9 IN V EN TOR.FRED P. SCHLICHTING ATTORNEY Unite States Patent ice Patented Feb. 12,1953 outlet end of the mixture conduit and is connected by 3,977,341means of a suitable linkage it) to an accelerator pedal CARBURETQRFrederick P. Schlichtlng, Beliefontaine Neighbors, Mm, asslgnor to ACFindustries, Incorporated, New Yer-u, N.Y., a corporation of New JerseyFiled Apr. l, 1959, Ser. No. 19,243 3 Claims. (til. 261-39) Thisinvention relates to carburetors for internal combustion engines, andmore particularly'to means for controlling the fuel mixture supplied tothe engine by the idle fuel system.

in the operation of conventional carburetors, the idle fuel system isadapted to supply a small quantity of fuel and air to the engine whenthe throttle valve is in closed or nearly closed position. During rapiddeceleeration of a vehicle with the throttle valve closed, an excessquantity of fuel is drawn from the idle fuel system into the engine andis exhausted to atmosphere, thereby contaminating the atmosphere andwasting fuel. During idle operation of an engine at high underhoodtemperatures, it is desirable to lean out the idle fuel mixture toincrease the speed of the engine to prevent stalling.

it is, therefore, an object of the invention to provide a carburetorwith means for leaning out the fuel mixture supplied to an engine by theidle fuel system during deceleration and hot idle operation of anengine.

Another object of the invention resides in the provision of meansadapted to be applied to conventional carburetors for controlling thefuel mixture supplied to an engine by tie idle fuel system.

A further object of the invention resides in the provision of an idleadjustment screw provided with means for controlling the ratio of fuelto air supplied to an engine by the idle fuel system.

Another object of the invention resides in the provision of an idleadjustment screw provided with an air inlet passage controlled by aninlet check valve operable responsive to suction posterior of thethrottle valve, whereby a leaner fuel mixture is supplied to the engineduring deceleration.

Another object of the invention resides in the provision of an idleadjustment screw provided with a thermostat operable responsive to anincrease in ambient temperature to open a valve in the air inlet passagein the adjustment screw to provide the engine with a leaner fuel mixtureunder hot idle conditions.

The invention embodies other novel features, details of construction andarrangement of parts which are hereinafter set forth in thespecification and claims and illustrated in the accompanying drawing,forming part thereof, wherein:

FIG. 1 is a vertical section, partly in side elevation, showing acarburetor provided with an idle fuel system control means embodyingfeatures of the invention.

PEG. 2 is an enlarged longitudinal section illustrating the controlmeans for the idle fuel system.

Referring now to the drawing for a better understanding of theinvention, a downdraft carburetor is shown as comprising air hornsection 2, a main body section 3, and an outlet section 4, said sectionsbeing secured together and forming a mixture conduit 6 having a stack ofventuris 7, 7a and 7b in the main body section. The carburetor ismounted on the intake manifold M of a conventional internal combustionengine N adapted for use in driving a vehicle.

A conventional choke valve control mechanism, operable responsive tointake manifold suction and temperature, is adapted to be provided tocontrol the operation of a choke valve 9 provided in the air inlet endof the mixture conduit 6. A throttle valve 8 is disposed in the forcontrol by the operator.

The main body section 3 is provided with a fuel bowl 12 having a fuelinl t 13 provided with a screen filter 14 and a fuel inlet valve 16. Afloat i7 is pivotally mounted at 13 Within the fuel bowl to actuate thevalve to maintain a substantially constant fuel level within the bowl.Fuel is supplied to the bowl from a fuel tank T by means of aconventional engine operated fuel pump P interposed in a fuel conduit 25leading to the fuel inlet 13.

A fuel metering orifice 19 leads from the fuel bowl to an upwardlyinclined main fuel passage 21 having a main fuel nozzle 22 discharginginto the primary venturi 7. An idling fuel system is shown as comprisinga fuel well 23 leading upwardly from the main passage 21, the wellhaving a metering tube 24 therein communicating with an idle passage 26leading to idle ports 27 and 28 in the outlet section 4. The outletsection 4 is provided with an internally threaded passage 2% coaxialwith the idle port 28 to receive the threaded portion 31 of an idle fuelcontrol device 32.

The idle fuel control device 32 is shown as comprising an elongated body33 formed at one end with a conical tip 34 for registry with the idleport 28 to control the flow of fuel therethrough during idle operationof an engine under normal conditions. The body 33 is provided With alongitudinal passage 36 having a coaxial air inlet port 37 and an airoutlet port 38 leading into the passage 29.

The inlet port 37 is formed in a seat ring 39 presstted within a bore 41formed in the end of the body 33. The seat ring 3? is formed with anannular valve seat for engagement by a spherical valve member 42 whichis normally held against the seat by a compression spring 43 seatedagainst a shoulder 44.

A hot idle air intake port 46 is formed in the body 33 adja cut theouter end thereof to bleed air into the passage 36 under control of avalve element 47 provided on one end of a bimetal thermostat secured tothe body by means of a screw or rivet 49, the valve element 47 beingseated in the port during normal ambient temperatures.

In operation, the control device 32 may be threaded toward or away fromthe idle port 28 to adjust the flow of fuel from the idle fuel system toan engine to control the idling speed of the engine.

During hot weather and high underhood temperatures, it is desirable tolean out the idle fuel mixture to an engine to prevent stalling. Thisresult is accomplished by means of the thermostat is which acts to movethe valve element 47 away from the port 46 to permit a flow of airthrough the passage 36 to the idle port 28.

When the throttle valve S is closed to decelerate a vehicle, it isdesirable to bleed air into the idle system to reduce the quantity offuel delivered to the engine. By providing a spring biased check valve42 in the air inlet port 37 to open at high suction posterior to thethrottle valve, additional air is bled through the passage 36 and port28 to lean out the fuel mixture supplied to the engine.

Certain structures have been shown and described herein which willfulfill all the objects of the present invention, but it is contemplatedthat other modifications will be obvious to those skilled in the artwhich come within the scope of the invention as defined by the appendedclaims.

I claim:

1. A carburetor for an internal combustion engine comprising a mixtureconduit having an outlet portion .eidapted-to be mounted on an engineintake'manifold,

a throttle valve in said conduit outlet portion, means forming an idlefuel system in said carburetor and including an idle port opening intosaid mixture conduit posterior to said throttle valve to discharge fuelinto said conduit, an internally threaded passage in said conduit outletportion connecting said idle port to the exterior of said carburetor, acombined hot idle compensator and degasser device comprising anelongated body having one inner end in threaded engagement in saidpassage and another portion thereof extending outside said mixtureconduit outlet portion, a conical tip on said inner end of said body inregistry with said idle port, an air passage in said body extendingaxially therethrough and having first and second air inlet ports in saidother body portion opening outside said carburetor and an air outletport connected to said threaded passage to supply air to said internallythreaded passage, a check valve means in said axially extending airpassage normally closing said first air inlet'port and responsive tosuction, posterior of said throttle valve in said air passage to leanout the idle fuel mixture supplied to the engine during deceleration, avalve normally closing said second inlet port to control air flowthrough said second air inlet port, and means outside said carburetorand fixed to the exposed surface of said other body portion responsiveto an increase in ambient temperature to open said air control valve tolean out the idle fuel mixture supplied to the engine.

2. The invention of claim 1 wherein said temperature responsive meansincludes a bimetallic spring strip having one end fixed to said exposedbody portion surface and the other end thereof fixed to said air controlvalve.

3. The invention of claim 2, wherein said air control valve includes afrusto-conical valve element mounted on said bimetallic strip inregistry with said second inlet port.

References Cited in the file of this patent UNITED STATES PATENTS

1. A CARBURETOR FOR AN INTERNAL COMBUSTION ENGINE COMPRISING A MIXTURECONDUIT HAVING AN OUTLET PORTION ADAPTED TO BE MOUNTED ON AN ENGINEINTAKE MANIFOLD, A THROTTLE VALVE IN SAID CONDUIT OUTLET PORTION, MEANSFORMING AN IDLE FUEL SYSTEM IN SAID CARBURETOR AND INCLUDING AN IDLEPORT OPENING INTO SAID MIXTURE CONDUIT POSTERIOR TO SAID THROTTLE VALVETO DISCHARGE FUEL INTO SAID CONDUIT, AN INTERNALLY THREADED PASSAGE INSAID CONDUIT OUTLET PORTION CONNECTING SAID IDLE PORT TO THE EXTERIOR OFSAID CARBURETOR, A COMBINED HOT IDLE COMPENSATOR AND DEGASSER DEVICECOMPRISING AN ELONGATED BODY HAVING ONE INNER END IN THREADED ENGAGEMENTIN SAID PASSAGE AND ANOTHER PORTION THEREOF EXTENDING OUTSIDE SAIDMIXTURE CONDUIT OUTLET PORTION, A CONICAL TIP ON SAID INNER END OF SAIDBODY IN REGISTRY WITH SAID IDLE PORT, AN AIR PASSAGE IN SAID BODYEXTENDING AXIALLY THERETHROUGH AND HAVING FIRST AND SECOND AIR INLETPORTS IN SAID OTHER BODY PORTION OPENING OUTSIDE SAID CARBURETOR AND ANAIR OUTLET PORT CONNECTED TO SAID THREADED PASSAGE TO SUPPLY AIR TO SAIDINTERNALLY THREADED PASSAGE, A CHECK VALVE MEANS IN SAID AXIALLYEXTENDING AIR PASSAGE NORMALLY CLOSING SAID FIRST AIR INLET PORT ANDRESPONSIVE TO SUCTION POSTERIOR OF SAID THROTTLE VALVE IN SAID AIRPASSAGE TO LEAN OUT THE IDLE FUEL MIXTURE SUPPLIED TO THE ENGINE DURINGDECELERATION, A VALVE NORMALLY CLOSING SAID SECOND INLET PORT TO CONTROLAIR FLOW THROUGH SAID SECOND AIR INLET PORT, AND MEANS OUTSIDE SAIDCARBURETOR AND FIXED TO THE EXPOSED SURFACE OF SAID OTHER BODY PORTIONRESPONSIVE TO AN INCREASE IN AMBIENT TEMPERATURE TO OPEN SAID AIRCONTROL VALVE TO LEAN OUT THE IDLE FUEL MIXTURE SUPPLIED TO THE ENGINE.